1. Field of the Invention
This invention relates to the construction of buildings and is specially concerned with building elements subjected to weather, for example, roofs and walls, and with components of these elements, for instance, coatings.
A specific utility of the invention is in providing an improved form of Bermuda roof. This type of roof will, therefore, serve as a convenient starting point for the understanding of the invention, although it must be understood that the invention is not limited to this use. The Bermuda roof has a sloping deck clad with a plurality of limestone slabs over-lapped to provide a stepped or contoured surface which is covered with paint or a cement wash to render it waterproof. This roof has a characteristic appearance as will be readily recognized by anybody who has visited Bermuda.
Applying the invention to the construction of a Bermuda roof, the stone slabs are replaced by wedge-shaped interfitting insulating shingles of substantially impervious synthetic resin closed cell foam firmly secured to the deck, to form a continuous insulating blanket. The blanket is covered by a load-bearing impact-resistant weather impervious sheath. The sheath is made up of a hard, essentially reinforced concrete shell adhering tenaciously to the top surface of the shingles and an essentially rubbery-textured membrane covering the shell and adhering tenaciously to it. Critical characteristics of the sheath materials and advantageous detailed features of construction which may be accomplished by their use will be described as this disclosure progresses.
2. Description of the Prior Art
The general prior art of constructing roofs and walls is replete in the use of synthetic resin foam in combination with other structural and coating material. For example, one patent, which, at first glance, might be considered analogous to the applicant's development, is directed to cladding a flat surfaced wall or roof, employing a plurality of resilient thermo-insulating cellular polystyrene plates to form an insulating layer covering the wall or roof support. Over the insulating layer there is applied a continuous intermediate layer consisting essentially of a synthetic resin having a reinforcing glass fabric embedded in it. The patentee describes the intermediate layer as being of polyvinyl chloride or a butadiene styrene copolymer, having quartz powder distributed throughout and a propionic acid binder which he says may be mixed with an equal amount of Portland cement. On the free outer face is formed a continous plaster coating, consisting essentially of a mixture of quartz and synthetic resin cementitious material, which the patentee suggests may be formed of propionic acid ester.
This prior art has the following characteristics. Polyvinyl chloride deteriorates on ultraviolet exposure and gives off corrosive hydrogen chloride. Polyvinyl chloride film blackens and brittles and requires plasticizers for usable flexibility. Butadiene styrene polymers oxidize in ultraviolet light with severe yellowing and embrittlement due to cross-linking. They require the use of antioxidants. Propionic acid esters and polyvinyl acetates hydrolize in the presence of moisture and alkali.